docs: def purge(calc_id):
      """
      Remove the given calculation. If you want to remove all calculations,
      use oq reset.
      """
      if calc_id < 0:
          try:
              calc_id = datastore.get_calc_ids(datadir)[calc_id]
          except IndexError:
              print('Calculation %d not found' % calc_id)
              return
      purge_one(calc_id, getpass.getuser())